191 



The figures of returns of the yields of rubber trees in the Amazons 

 vary very much. In the lower Amazon some estates go as low as a 

 pound a tree, others giving 2 to 3 pounds a season. "VVhen certain 

 estates on the island of Marajo were sold a yield of nefatrly 9 pounds 

 a tree was estimated. They worked out however to about 7 pounds 

 a tree. A prospectus of an estate near Manaos claimed 17 pounds, 

 while an expert estimated the amount at 10 pounds a tree. Conway* 

 speaking of yields in Bolivia, estimated that they were never les? 

 than 3lbs. nor more than 7, which Mr. Pearson thinks approximately 

 correct, but he points out that trees vary not only in size but in 

 productiveness, and that trees that have been tapped for years give 

 somewhat less than those that have only been tapped for a short time. 



There is a great deal more of interest in this nicely got up and 

 charmingly illustrated volume, which is well worth reading by all 

 interested in rubber.- Ed. 



TRAVELLING OF RUBBER SEED. 



In certain correspondence as to success an-! failure in seed of Para 

 rubber sent from the Malay Peninsula to British Guiana some 

 investigations of Mr. T. B. Harrison, the Director of the Botanic Gai - 

 <lens there, are of sufficient importance to be noted. 



Seed from good trjes were sent from the Singapore Botani^'> 

 -Gardens, and from a locality in the Native States, in a number of 

 instalments. Of these, on arrival at their destination, after a long 

 journey about fifty nine days, those from Singapore germinated at the 

 rate of 702 per thousand, while of the other senrfings only 19 per 

 housand germinate l. 



Both series were pricked in tin boxes with ( iiarred rice dustj but 

 with these differences, the seeds from Singapoi e 'vere packed only 600 

 in a tin, the others contained on an average 823 in each tin so closely 

 packed that they almost quite touched, and the .Singapore boxes were 

 only closed, the others hermetically soldered down. 



The percentage of moistur*:^ in the charcoal varied from 5109 [jlt 

 •cent., but these variations apparently exercised little if any influence 

 <m the rate of gern^i nation. When the packages of the spoiled seech 

 were opened they were found to be slightly warm and evolved a 

 strong and penetrating oJour. The charred rice husk of the package 

 was ex:unined and fonn.j to 'coiitain hydrocyanic acid in minute 

 amount, formaldehyde in traces, formic a jid in some quantity and 

 acetic acid in abundance. The seeds were in fact pickled in the pro- 

 ducts of their own decomposition. It was 'noticeable that the 

 proportion of hydrocyanic acid in th^ vapours''(jf the seeds varies! 

 •considerably, the amount present in the last shipment received (of 

 whicli only 16 per thousand germinated) being en')i;gh to cause a 

 transient illness in the persons opening the package^. 



